Jugular foramen schwannomas: surgical approaches and outcome of treatment

Twelve cases of schwannomas of the jugular foramen that involved surgery in our department between 1983 and 1997 are described. Eight were women and 4 were men (mean age, 40 years), and the duration of their symptoms, the most predominant of which were hearing loss and tinnitus, ranged from 1 month to 20 years (median, 8.5 months). Depending on their radiological and surgical features, tumors were classified as type A, a tumor primarily at the cerebellopontine angle with minimal enlargement of the jugular foramen (n = 5); type B, a tumor primarily at the jugular foramen with or without intracranial extension (n = 4); type C, a primarily extracranial tumor with extension into the jugular foramen (n = 0); or type D, a dumbbell tumor with both intracranial and extracranial components (n = 3). A retrosigmoid suboccipital craniectomy (RSSOC) was performed for type A tumors; for types B and D, the RSSOC or staged infratemporal fossa approach (ITFA)/RSSOC was used. Total removal was achieved in 6 cases, near total removal in 3, and subtotal removal in 3. The most common complication was lower cranial nerve dysfunction (n = 5). The follow-up period ranged from 6 to 173 (mean, 48) months, and there was no recurrence. Two patients showed regrowth of the tumor after subtotal resection, however. In 1 of these, the residual tumor had progressed within 12 months of initial surgery, it was again resected and linac radiosurgery was successful. In the other, the residual mass had progressed within 8 months of initial surgery, and the pathological report indicated malignant peripheral nerve sheath tumor. Conclusively, type A tumors could be totally resected with the retrosigmoid approach alone. For type B and D tumors, however, combined ITFA and retrosigmoid approach showed the better results. In spite of our limited data, cases showing adhesion to critical structures can be managed by subtotal or near total resection followed by radiosurgery to reduce postoperative complications.

Compensation of motion artifacts in catheter-based optical frequency domain imaging

A novel heterodyne Doppler interferometer method for compensating motion artifacts caused by cardiac motion in intracoronary optical frequency domain imaging (OFDI) is demonstrated. To track the relative motion of a catheter with regard to the vessel, a motion tracking system is incorporated with a standard OFDI system by using wavelength division multiplexing (WDM) techniques. Without affecting the imaging beam, dual WDM monochromatic beams are utilized for tracking the relative radial and longitudinal velocities of a catheter-based fiber probe. Our results demonstrate that tracking instantaneous velocity can be used to compensate for distortion in the images due to motion artifacts, thus leading to accurate reconstruction and volumetric measurements with catheter-based imaging.

RF Magnetic Signal Localization at Very High Magnetic Field Systems

The impetus of this work originated from the advent of high magnetic field magnetic resonance imaging scanners with B0 fields of 4T, 7T, and 9.4T. These ultrahigh magnetic field systems generally improve the signal to noise ratios. However, B1 field non-uniformity also occurs due to the increased RF field frequencies when wavelengths in the head become shorter than its size. As interest in multiple channel transmission line coils increases, the control of the amplitude and phase of individual coil elements is required in order to develop desired B1 field. The choice of the excitation of the coil elements may be determined by convex optimization. Convex optimization is used provides results very fast, when the problem is formulated globally. In addition, convex optimization provides better signal to noise (SNR) ratio when anatomic specific regions are investigated. In this paper, simulation and experimental results are discussed at 9.4T systems based on the number of elements. The primary objective of this study is to increase the signal in a specific target region and decrease the signal and noise in the outside region termed the suppression region. The convex formulations are minimizing the maximum field point in the suppression region while keeping the center of target maximum. Based on this min-max optimization criterion, an iteration method which modifies the selection of suppression fields is also performed to produce better results. The results of the localization on FDTD human data at 9.4T are shown in Fig. 1. In these figures, the axial slices of the center of human head model provided by XFDTD are used after manipulating with MATLAB and the 16 channel head coil is excited. Figure 1 shows an improvement of the homogeneity in the suppression region when the target region is at center. In Fig. 2, received signal localizations are obtained for three different regions of interest (ROI) after using the convex optimization. Note that the selection of ROI is limited by the geometric setting of phantom in the 8-channel TEM head coil. Convex optimization with an iterative method was performed on both the human head and phantom models with operating frequency 400 MHz to design coil channel excitation parameters. By applying the iterative method to the convex optimization, more homogeneous B1 fields are obtained in the suppression region for 9.4T system.

Predictors of outcome in patients with unresectable hepatocellular carcinoma receiving transcatheter arterial chemoembolization

BACKGROUND

Transcatheter arterial chemoembolization (TACE) has been shown to improve survival in patients with unresectable hepatocellular carcinoma (HCC).

AIM

To identify pretreatment factors that predicts increased mortality in HCC patients receiving TACE.

METHODS

Retrospective review of all patients who underwent TACE for HCC from January 1999 to November 2004. Patient demographics, aetiology of liver disease, laboratory and imaging data regarding tumour characteristics were obtained.

RESULTS

Eighty-eight patients (57 +/- 1 years age) received 1-4 sessions of TACE (1.4 +/- 0.1). Tumour size was 3.3 +/- 0.2 cm (range 1-13 cm, median 3 cm) with mean number of lesions 1.9 +/- 0.1 (range 1-7). Mean model for the end stage liver disease score: 11 +/- 0.4; cancer of the liver Italian program score: 1.3 +/- 0.1. Survival post-TACE (excluding those underwent orthotopic liver transplantation) was 12 +/- 0.3 months. By multivariate analysis, tumour size (HR = 1.37, 95% CI: 1.11-1.68, P = 0.003), hypovascularity (HR = 12.62, 95% CI: 1.79-88.92, P = 0.01) and elevated international normalized ratio (HR = 1.46, 95% CI: 1.10-1.92 P = 0.008) are shown to be significant risk factors for increased mortality.

CONCLUSION

TACE therapy leads to a mean survival of 12 months in patients not receiving orthotopic liver transplantation. Tumour size, hypovascularity on imaging, and elevated international normalized ratio are predictors of increased mortality after TACE therapy for HCC.

Preoperative level of VEGF and IL-6 are associated with lymph node invasion and stage in gastric cancer

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Introduction: Angiogenesis plays an important role in growth, progression, and metastasis of tumors, and various cytokines are associated with the spread of cancer cell. In this study, we evaluate the role of VEGF and IL-6 in predicting the spread of gastric cancer. Methods: Preoperative one hundred twenty seven gastric cancer patients and 88 healthy subjects’ specimens were examined. The association of VEGF and IL-6 level with clinical and pathological findings was evaluated Results: Serum VEGF and IL-6 level in gastric cancer patients were higher than those in control (P<0.001, P=0.006, respectively). VEGF and IL-6 level were associated with presence of LN metastasis (P=0.003, P=0.041, respectively). IL-6 level was correlated with stage (P=0.012) and depth of invasion (P=0.018). VEGF level was correlated with invasion of lympho-vascular structure (P=0.021). VEGF and IL-6 level was not related to differentiation, size or CEA level. Conclusions: Serum VEGF and IL-6 levels in gastric cancer patients are higher than those in control. Preoperative VEGF and IL-6 levels could be a predictive marker of tumor invasion and LN metastasis.

No significant financial relationships to disclose.

Covered stent application of a repeatedly regrowing iatrogenic subclavian artery pseudoaneurysm at the origin of the vertebral artery

SUMMARY

Formation of an iatrogenic subclavian artery pseudoaneurysm while attempting central venous access through the internal jugular vein is relatively uncommon. However, management of a subclavian artery pseudoaneurysm remains a challenge because of its growing tendency and its relation to the origin of the vertebral artery (VA). We report a strategy for using a covered stent as for the endovascular treatment of a patient with a repeatedly regrowing subclavian artery pseudoaneurysm at the origin of the VA.